As in a wide variety of other machinery, a spring winding machine of the type commonly known as a torsion spring winder requires that master and slave rotary elements be interconnected and driven in a specific timed relationship. More particularly, the master element or cam shaft in a torsion winder and the slave element or spindle must be rotated at various preselected relative angular velocities in order to provide for desired spring characteristics. That is, the number of turns in the springs to be produced may vary widely over a range and, accordingly, the number of spindle revolutions per cam shaft revolution must be capable of precise control and adjustment over a wide range.
Mechanical and other means have heretofor been provided for maintaining the desired relationship between master and slave elements or cam shaft and spindle in torsion winders but have been found lacking in the desired ease and convenience of adjustment, flexibility, etc. Illustrative examples of spring winding machines may be found in U.S. Pat. No. to Sampatacos et al. 2,697,470, Sampatacos et al. U.S. Pat. No. 2,788,807 and Cavagnero et al. U.S. Pat. No. 3,433,041.